我收到NullPointerException代码，
package com.example.extra;
import java.util.List;
import com.example.dto.DriverSelectedRouteArrayList;
import com.example.main.R;
import android.content.Context;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ArrayAdapter;
import android.widget.BaseAdapter;
import android.widget.CheckBox;
import android.widget.CompoundButton;
import android.widget.TextView;
public class CustomerAdapter extends BaseAdapter
{
DriverSelectedRouteArrayList driverSelectedRouteArrayList;
private List<DriverSelectedRouteArrayList> list;
private LayoutInflater layoutInflater;
Context context;
ViewHolder holder;
public CustomerAdapter(Context context, int resource, List<DriverSelectedRouteArrayList> driverData)
{
this.list = driverData;
this.context = context;
layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
}
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
View view = convertView;
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
view = inflater.inflate(R.layout.student_list_view_itom, null);
if(view == null)
{
TextView textViewRouteId = (TextView) view.findViewById(R.id.srNumberTextView);
// convertView = layoutInflater.inflate(R.layout.student_list_view_itom, null);
holder = new ViewHolder();
holder.srNumberTextView = (TextView) convertView.findViewById(R.id.srNumberTextView);
holder.nameTextView = (TextView) convertView.findViewById(R.id.textViewStudentItem);
holder.phoneNumberTextView = (TextView) convertView.findViewById(R.id.textViewPhoneNumber);
holder.checkBox = (CheckBox) convertView.findViewById(R.id.checkBoxSelectForStudentList);
holder.checkBox
.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
@Override
public void onCheckedChanged(CompoundButton buttonView, boolean isChecked)
{
int getPosition = (Integer) buttonView.getTag();
list.get(getPosition).setSelected(buttonView.isChecked());
}
});
view.setTag(holder);
view.setTag(R.id.checkBoxSelectForStudentList,holder.checkBox);
view.setTag(R.id.srNumberTextView,holder.srNumberTextView);
view.setTag(R.id.textViewStudentItem, holder.nameTextView);
view.setTag(R.id.textViewPhoneNumber, holder.phoneNumberTextView);
}else{
holder = (ViewHolder) view.getTag();
}
holder.checkBox.setTag(position);//error in this line
Log.e("get position=======>", ""+list.get(position).get_id());
holder.srNumberTextView.setText(String.valueOf(list.get(position).get_id()));
holder.nameTextView.setText(list.get(position).getFirst_name()+" "
+list.get(position).getMiddle_name()+" "
+list.get(position).getLast_name());
holder.phoneNumberTextView.setText(list.get(position).getPhone_number());
holder.checkBox.setChecked(list.get(position).isSelected());
return view;
}
static class ViewHolder
{
protected TextView srNumberTextView;
protected TextView nameTextView;
protected TextView phoneNumberTextView;
protected CheckBox checkBox;
}
@Override
public int getCount() {
// TODO Auto-generated method stub
return list.size();
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return list.get(position);
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return position;
}
}
标题LogCat：
01-06 07:42:53.132: E/AndroidRuntime(3300): FATAL EXCEPTION: main
01-06 07:42:53.132: E/AndroidRuntime(3300): Process: com.example.main, PID: 3300
01-06 07:42:53.132: E/AndroidRuntime(3300): java.lang.NullPointerException
01-06 07:42:53.132: E/AndroidRuntime(3300): at com.example.extra.CustomerAdapter.getView(CustomerAdapter.java:73)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.widget.AbsListView.obtainView(AbsListView.java:2263)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.widget.ListView.measureHeightOfChildren(ListView.java:1263)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.widget.ListView.onMeasure(ListView.java:1175)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.View.measure(View.java:16497)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.widget.RelativeLayout.measureChild(RelativeLayout.java:689)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:473)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.View.measure(View.java:16497)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.View.measure(View.java:16497)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
01-06 07:42:53.132: E/AndroidRuntime(3300): at com.android.internal.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:327)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.View.measure(View.java:16497)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.widget.FrameLayout.onMeasure(FrameLayout.java:310)
01-06 07:42:53.132: E/AndroidRuntime(3300): at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.View.measure(View.java:16497)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1916)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1113)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1295)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1000)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5670)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.Choreographer.doCallbacks(Choreographer.java:574)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.Choreographer.doFrame(Choreographer.java:544)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.os.Handler.handleCallback(Handler.java:733)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.os.Handler.dispatchMessage(Handler.java:95)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.os.Looper.loop(Looper.java:136)
01-06 07:42:53.132: E/AndroidRuntime(3300): at android.app.ActivityThread.main(ActivityThread.java:5017)
01-06 07:42:53.132: E/AndroidRuntime(3300): at java.lang.reflect.Method.invokeNative(Native Method)
01-06 07:42:53.132: E/AndroidRuntime(3300): at java.lang.reflect.Method.invoke(Method.java:515)
01-06 07:42:53.132: E/AndroidRuntime(3300): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
01-06 07:42:53.132: E/AndroidRuntime(3300): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
01-06 07:42:53.132: E/AndroidRuntime(3300): at dalvik.system.NativeStart.main(Native Method)
答案 0 :(得分：5)
更改为
holder.srNumberTextView = (TextView) view.findViewById(R.id.srNumberTextView);
其他观点也一样。使用view.findViewById代替convertView.findViewById。
layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
// already initialized in the constructor of adapter class
// no need to initialize in getView
你需要移动
holder.checkBox.setOnCheckedChangeListener
如果部分
你有
int getPosition = (Integer) buttonView.getTag();
甚至在你将标签设置为复选框之前。
可能还有其他错误。我指出了一些我可以睁开眼睛的事。
@Override
public View getView(int position, View convertView, ViewGroup parent)
{
ViewHolder holder;
if(convertView == null)
{
convertView = layoutInflater.inflate(R.layout.student_list_view_itom, null);
holder = new ViewHolder();
holder.textViewRouteId = (TextView) convertView.findViewById(R.id.srNumberTextView);
holder.srNumberTextView = (TextView) convertView.findViewById(R.id.srNumberTextView);
holder.nameTextView = (TextView) convertView.findViewById(R.id.textViewStudentItem);
holder.phoneNumberTextView = (TextView) convertView.findViewById(R.id.textViewPhoneNumber);
holder.checkBox = (CheckBox) convertView.findViewById(R.id.checkBoxSelectForStudentList);
convertView.setTag(holder);
}else{
holder = (ViewHolder) convertView.getTag();
}
// update your views here
return convertView;
}
然后
static class ViewHolder
{
protected TextView srNumberTextView,textViewRouteId;